Aerosol generator



Oct. 28, 1958 P. A. FRANK 2,358,162

AEROSOL GENERATOR Filed Dec. 14, 1953 2 Sheets-Sheet 1 FIG-1 INVEN'TOR. PAUL A. FRANK BY wzfi ATTORNEYS Get. 28, 1958 FRANK 2,858,162

AEROSOL GENERATOR Filed Dec. 14, 1953 2 Sheets-Sheet 2 IA'IIIIIIIMIQ IN VEN TOR.

PAUL A. FRANK ATTORNEYS United States Pate AEROSOL GENERATOR Paul A. Frank, Bedford, Ind., assignor to William L. Tenney, Dayton, Ohio Application December 14, 1953, Serial No. 397,829

8 Claims. (Cl. 299-86) This invention relates to fog and spray generators and more particularly to such generators of the pulse jet engine type.

A pulse jet engine has certain advantages from the standpoint of simplicity of construction and operation, small numberof moving parts, and economy in size, weight and expense. Where such an engine is incorporated in a device for vaporizing or atomizing and distributing a formulation in the form of a fog or spray and including special materials such as an insecticide or the like for special purposes, it is important to retain these advantages which are associated with the engine itself. At the same time, it is important that such a fog and spray generator as a whole be of such constructional and operational characteristics as to minimize possible interruption of operation by accident during use, and this is especially true in the case of such a generator utilized in military or naval operations to produce a smoke screen.

It is an object of the present invention to provide a fog and spray generator of the pulse jet engine type which does not require a pressurized and hence a sealed reservoir for the fog or spray producing formulation and which is completely operable with an open reservoir or tank which is thus not subject to being incapacitated by loss of pressure of a sealed reservoir.

Another object is to provide a fog and spray generator of the pulse jet engine type which is of such construction and arrangement as to provide high pumping pressures for the fog or spray producing formulation and especial 1y which possesses a reserve of pressure capable of assuring successful operation under special conditions such as with heavy oils and in cold weather.

It is also an object of the present invention to provide a fog and spray generating engine of the pulse jet type in which stopping of the engine will automatically cause prompt stopping of the flow of fog or spray producing formulation to the engine without requiring special safety mechanism, and thus to assure adequate safety against fire and undesirable loss of formulation with an economical construction and a minimum of special parts.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawing:

Fig. 1 is a somewhat schematic layout of a fog and spray generating apparatus constructed in accordance with the invention;

Fig. 2 is a fragmentary view similar to Fig. 1 showing a modified arrangement;

Fig. 3 is a view partly in elevation and partly in sec- 6 tion on the line 33 of Fig. 4 showing the positive displacement pump and driving fluid motor therefor in the system of Fig. 1;

Fig. 4 is a fragmentary plan view of the pump portion of the apparatus shown in Fig. 3;

Fig. 5 is a detail sectional view through the pressurizing valve in the apparatus of Fig. 1; and

2,858,162 Patented Oct. 28, 1958 ice Fig. 6 is a diagrammatic view illustrating the opera tion of the pump of Figs. 3 and 4.

Referring to the drawings, which illustrate preferred embodiments of the invention, the apparatus shown in Fig. 1 embodies a resonant pulse jet engine indicated generally at if), a suitable engine for this purpose being disclosed in more detail in Tenney et al. Patent No. 2,609,660 issued September 9, 1952 to the assignee of this application. In general, such an engine embodies a fuel supply line 11, an auxiliary air connection 12 supplied from the hand pump 13 for starting purposes, a combustion chamber 15 with a spark plug 16 therein for initiating combustion, and an elongated discharge tube 117 connected with the end of the combustion chamber by a conical connecting portion 18. Such an engine embodies the combination of a combustion chamber, valved inlet ports and a discharge tube forming a system resonant in gases which operates, after being started, with self-induced charging, ignition and scavenging, thus constituting a resonant intermittent combustion device.

The system also embodies a starting battery 20 controlled by a switch 21 which closes the circuit to the spark coil 22, providing the high tension ignition spark for spark plug 16. An indicating device 25 may be used to show when the ignition circuit is closed and outside terminals 26 may be providedfor connection to an external battery source when desired. As will be understood, the hand pump and the spark coil are required only for initial starting purposes, the engine thereafter continuing to function without the use of either the hand pump or the spark coil as more fully described in said prior patent.

Fuel for operating the engine is contained in fuel tank 30 and is shown as passing by gravity action through line 31 to a filter 32 and float chamber 33 directly to the fuel line 11, the latter being under control of manual shutoff valve 35, and if desired, a conventional fuel pump may be connected in the feed line or the pressure developed in the combustion chamber 15 may be supplied to the fuel tank to force the fuel through the feed line as shown in the Tenney et al. Patent No. 2,768,031, issued October 23, 1956, and assigned to the same assignee as this application. Suitable cooling means should also be provided for the engine Ill, which may also be constructed as shown in said copending application.

The liquid formulation for producing the fog or spray may be contained in any suitable container or reservoir open to atmospheric pressure such as the drum 40. This formulation is shown as withdrawn from the reservoir through a pickup line 41 provided with a filter 42 and having its inlet end equipped with a suitable weight device d3 preventing the line from attaching itself to the bottom of the reservoir by suction. The formulation is supplied to the discharge tube 17 by means of a positive displacement pump indicated generally at 44 in Fig. l operated by a fluid motor 45 which in turn receives its operating pressure from the combustion chamber 15. This pressure is developed through the provision of the pressurizing valve 46 which is shown in detail in Fig. 5 and is connected with the combustion chamber 15 by a tube 47 capable of withstanding the relatively high temperatures encountered adjacent the engine. The tube 4.7 has sufficiently large flow capacity and is sufficiently close to the engine so that it will effectively transmit to the pressurizing valve 46 the rapidly occurring but dis continuous high pressure peaks in the combustion chamber.

These pressure peaks are transmitted through a passage 48 in the inner valve body 50 and effect raising of the yieldable spring check valve member 51 against its back plate 52, to release such pressure peaks into the pressure chamber within the valve body 50. As soon as the pressure peak passes, the valve member 51 will close to prevent back flow, and thus only the pressure peaks of the combustion chamber are made effective Within the. valve chamber 53. With the entire pressurizing valve relatively close to. the engine and with its connecting line 47 of relatively low flow resistance as described, the pressure which is developed and maintained within chamber 53 will approach the maximum pressure intermittently produced in the combustion chamber itself, thereby developing continuous pressure Within chamber 50. A clean-out plug 54 is provided in the bottom of the pressurizing valve, and a pressure supply line 55 extends from the chamber 53 to the fluid motor 45, preferably by way of a dehumidifying filter 56 of suitable conventional construction.

The fluid motor 45 is provided with a control valve assembly indicated generally at 60 which receives the developed pressure from the line 55 and supplies it as the motivating fluid for operating the piston 61 reciprocating in the double ended cylinder 62 and having an extended piston rod 63 for driving the pump 44. The valve 60 includes a shift rod 65 operated by rocker arms 66 pivoted at opposite ends of the air motor housing in yokes 67 and operated in turn by push rods 68 which extend through opposite ends of the cylinder 62 for engagement alternately by the piston 61. The valve assembly 60 operates to connect the fluid pressure continuously to one side of the piston 61 and the other side of the piston to exhaust until the piston has substantially completed its stroke, and then immediately shifts to its other position supplying pressure to the opposite side of the piston while connecting the first side to exhaust. This valve construction assures against the possibility of the fluid motor stalling on dead center and also assures maximum efficiency, and satisfactory results from these'standpoints have been obtained with a valve of the construction shown in Klein et al. Patent No. 2,437,391, issued March 9, 1948 to Lincoln Engineering Company, St. Louis, Missouri.

The pump 44 is shown mounted as part of the same unit with the fluid motor 45 and includes a double ended cylinder 70 receiving a piston 71 on the opposite end of the piston rod 63 from the piston 51. The operation of this pump is readily apparent from the flow diagram in Fig. 6. The inlet line 41 is connected by a manifold 72 with the inlet chamber 73. A port 74 from chamber 73 into a chamber 75 is controlled by one end of a one-way reed valve 77, and a line 78 connects the chamber 75 with the end of cylinder 70. A similar port 79 controlled by the other end of the valve 77 leads from the chamber 73 into a chamber 80 from which a line 81 leads to the other end of cylinder 70. The chamber 75 is also connected with chamber 83 by a port 82 controlled by one end of a reed valve 85, and a port 86 controlled by the other end of reed valve 85 leads from a chamber 80 into the chamber 87. The chambers 83 and 87 are connected by a manifold 88 to a line 89 leading to the automatic shutoff valve and injection unit indicated generally at 90.

With this construction and arrangement of the pump 44, when the piston 71 moves to the left as viewed in Fig. 6, it will apply suction in chamber 75 causing the formulation to be drawn in past the valve 77 while holding the valve 85 in closing relation with the port 82, and this liquid will accordingly be drawn into the right hand end of cylinder 72. At the same time, pressure will be applied in the chamber 80 which will hold the valve 77 closed against port 79 while opening valve 85 at port 86 to expel the formulation into the chamber 87 and thence into the manifold 88 and line 89, and this discharge pressure will also 'be effective in chamber 83 to assist in holding valve 85 closed against port 82. When the piston reverses its stroke, the reverse conditions will obtain, with suction being applied in chamber 80 While pressure is exerted on the right hand end of cylinder 70 and chamber 75 to expel the contents thereof through port 82 into the line 89.

The structural parts of the pump 44 are constructed and arranged to provide the above operating characteristics as explained in connection with Fig. 6. The cylinder 70 is contained within the main pump housing 100, and the balance of the pump casing is formed by a plate 101 and castings 102 and 103 cooperating with spacers 184 and bolts 195. The curved formation of the metal portions of the castings 102 and 103 guide the opening movements of the reed valves 77 and as described. in addition, the several ports within the pump are each provided with a valve seat 106 having its upper surface rounded about a relatively short radius to facilitate opening of the valves, especially when pumping viscous fluids. The fitting 10? in Fig. 3 may be used with an oily formulation to provide for transmission of a small quantity of the liquid to the fitting 108 on the control valve 60 for lubricating purposes.

Care should be taken to proportion the pump motor 44 and fluid motor 45 to operate with optimum conditions of balance between the pressure and volume of gases available from the combustion chamber 15 and the volume of gaseous fluid required for operation of motor 45 to cause pump 44 to deliver the formulation to the engine at the desired rate and pressure. Thus the available power or energy may be computed as the product of the developed pressure and the volume of fluid utilized per minute to drive motor 45, and this power has a definite maximum depending upon the output characteristics of the supply from the engine 10. For optimum efficiency, therefore, the pump and motor should 'be proportioned to operate normally at slightly less than, the full available input power in order to assure a re-. serve of power in the event of abnormal operating conditions such as cold weather, heavy oil, andthe like.

In operation, as soon as the engine has been started,

the fluid motor 45 will begin to drive the pump 44, and,

thereafter the formulation will be supplied to the discharge tube 17. This operation will continue so long as the engine itself continues to operate and a supply of formulation remains available. Since the supply of formulation to the discharge tube is maintaining internal pressure within a sealed container, the apparatus of the invention is especially suitable for war-time use by reason of the fact that damage to the container or its seal will not interfere with continued operation, which may be maintained by simply transferring the pickup tube 41 to a fresh container. Also, it should be noted that with the pump 44 constructed as described, it is essentially self-priming by reason of the fact that it will retain liquid in its cylinder 70 and,

the several valve chambers after the motor is shut off.

Fig. 1 shows the connection unit from the line 89 tov the discharge tube 17 as including an automatic shutoff valve 110 controlled by pressure supplied by the connection 111 from the combustion chamber 15, and an adjustable control valve 112 which determines rate of flow of the formulation into the discharge tube 17. With this construction, as soon as the motor ceases to operate for any reason, the valve 110 will close to prevent furtherformulation being supplied to the discharge tube. This construction maybe desirable in some conditions to prevent the possibility of an oily.

formulation being supplied to the hot discharge tube after the engine has shut off, with resulting possibility of fire. dependent on positive displacement of pump 44 operated by engine pressure, stopping of the engine will necessarily stop the pump very shortly, so that for many installations, the automatic shutoff valve may be omitted. Thus as shown in Fig. 2, the line 89 may be provided with a simple direct connection 115 to the tube 17, preferably from the under side of the tube, so that when the engine stops, the resultant stopping of the,

not dependent upon On the other hand, with the oil supply being.

pump and the action of gravity will combine to prevent further supply of formulation to the discharge tube of the engine, and the control valve 116 corresponds to valve 112 and determines the rate of flow of the formulation through connection 115.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A fog and spray generator comprising a pulse jet engine including a combustion chamber and a discharge tube and adapted to develop a pulsating discharge pressure within the tube, a positive displacement pump having an intake adapted for connection to an open reservoir for storing a formulation for introduction into said tube to produce the fog or spray, means connecting the discharge side of said pump to said tube for delivering said formulation into said discharge tube, a fluid motor operatively connected in driving relation with said pump, means forming a pressure connection from said combustion chamber to said fluid motor, and a pressurizing valve in said pressure connection including a check valve member adapted to open for passage of the pressure peaks from said combustion chamber.

2. A fog and spray generator comprising a pulse jet engine including a combustion chamber and a discharge tube and adapted to develop a pulsating discharge pressure through the tube, a positive displacement pump having an intake adapted for connection to an open reservoir for storing a formulation for introduction into said tube to produce a fog or spray, means connecting the discharge side of said pump to said tube for delivering said formulation into said discharge tube, a fluid motor including a double acting cylinder and piston, means forming a driving connection from said piston to said pump, means forming a pressure connection from said combustion chamber to said fluid motor, and a pressurizing valve in said pressure connection including a check valve member adapted to open for passage of the pressure peaks from said combustion chamber.

3. A fog and spray generator comprising a pulse jet engine including a combustion chamber and a discharge tube and adapted to develop a pulsating discharge pressure through the tube, a positive displacement pump having an intake adapted for connection to an open reservoir for storing a formulation for introduction into said tube to produce the fog or spray, means connecting the discharge side of said pump to said tube for delivering said formulation into said discharge tube, a fluid motor including a double acting cylinder and piston, means forming a driving connection from said piston to said pump, means forming a pressure connection from said combustion chamber to said fluid motor, a pressurizing valve in said pressure connection including a check valve member adapted to open for passage of the pressure peaks from said combustion chamber, and a control valve for said motor constructed to supply the pressure from said pressurizing valve to said motor and to shift said pressure supply alternately to opposite sides of said piston at substantially the limit positions of said piston while simultaneously connecting the low pressure side of said piston to exhaust.

4. A fog and spray generator comprising a pulse jet engine including a combustion chamber and a discharge tube and adapted to develop a pulsating discharge pressure through the tube, a positive displacement pump having an intake adapted for connection to an open reservoir for storing a formulation for introduction into said tube to produce the fog or spray, an air motor operatively connected in driving relation with said pump, means forming a pressure connection from said combustion chamber to said air motor, a pressurizing valve in said pressure connection including a check valve member adapted to open for passage of the pressure peaks from said combustion chamber, and an open conduit connecting the discharge side of said pump to saiddischarge tube for delivery of said formulation to said tube providing for stopping of the flow of said formulation to said tube in response to stopping of said engine and the resultant cessation of the pressure supply to said pressurizing valve.

5. A fog and spray generator comprising a pulse jet engine including a combustion chamber and a discharge tube and adapted to develop a pulsating discharge pressure through the tube, a positive displacement pump having an intake adapted for connection to an open reservoir for storing a formulation for introduction into said tube to produce the fog or spray, an air motor including a double acting cylinder and piston, means forming a driving connection from said piston to said pump, means forming a pressure connection from said combustion chamber to said air motor, a pressurizing valve in said pressure connection including a check valve member adapted to open for passage of the pres sure peaks from said combustion chamber, a control.

valve for said air motor constructed to supply the pressure from said pressurizing valve to said air motor and to shift said pressure supply alternately to opposite sides of said piston at substantially the limit positions of said piston while simultaneously connecting the low pressure side of said piston to exhaust, and an open conduit connecting the discharge side of said pump to said discharge tube for delivery of said formulation to said tube providing for stopping of the flow of said formulation to said tube in response to stopping of said engine and the resultant cessation of the pressure supply to said pressurizing valve.

6. A fog and spray generator comprising a pulse jet engine including a combustion chamber and a discharge tube and adapted to develop a pulsating discharge pressure within the tube, a positive displacement pump including a double acting cylinder and piston, means defining an intake to said pump adapted for connection to an open reservoir for storing a formulation for introduction into said tube to produce the fog or spray, a conduit from said pump connected with said tube for delivering said formulation into said tube, valve means responsive to operation of said pump for connecting the low pressure side of said piston to said intake and connecting the high pressure side of said piston to said conduit, a fluid motor operatively connected in driving relation with said pump, means forming a pressure connection from said combustion chamber to said fluid motor, and a pressurizing valve in said pressure connection including a check. valve member adapted to open for passage of the pressure peaks from said combustion chamber.

7. A fog and spray generator comprising a pulse jet engine including a combustion chamber and a discharge tube and adapted to develop a pulsating discharge pressure within the tube, a positive displacement pump including a double acting cylinder and piston, means defining an intake to said pump adapted for connection to an open reservoir for storing a formulation for introduction into said tube to produce the fog or spray, a conduit from said pump for delivering said formulation into said tube, valve means responsive to operation of said pump for connecting the low pressure side of said piston to said intake and connecting the high pressure side of said piston to said conduit, an air motor including a double acting cylinder and piston, means forming a driving connection from said motor piston to said pump piston, means forming a pressure connection from said combustion chamber to said air motor, a pressurizing valve in said pressure connection including a check valve member adapted to open for passage of the pressure peaks from said combustion chamber, a control valve for said air motor constructed to supply the pressure from said pressurizing valve to said air motor andto shift said pressure supply alternately to opposite sides of-said motor piston at substantially the limit positions of said motor piston While simultaneously connecting the low pressure side of said motor piston to exhaust, and anopen connection from said conduit to said discharge tube for delivery of said formulation to said tube providing for stopping of the flow of said formulation to said tube in response to stopping of said engine and the resultant cessation of the pressure supply to said pressurizing valve.

8. A fog and spray generator comprising a pulse jet engine including a combustion chamber and a discharge tube and adapted to develop a pulsating discharge pressure Within the tube, a positive displacement pump including a double acting cylinder and piston, means defining an intake to saidpump adapted for connection to an open reservoir forstoring aforrnulation for introduction into said tube to produce the fog or spray, an air motor including ,a double acting, cylinder and piston, means forming apressure connection from said combustion chamber to said air motor, a pressurizing valve in said pressure connection including a check valve member adaptedto open for passage of the pressure peaks from said combustion chamber, a controlvalve for said air motor constructed to supply the'pressure from said pressun'zing valve to, said air motor and to shift said pressure supply alternately to opposite sides of said motor piston at substantially the limit positions of said motorpiston while simultaneouslyconnecting the low pressure side of said motor piston to exhaust, means forming a driving connection from said motor piston to said pump piston, a conduit connecting said pump to said tube for delivering said formulation into said'tube, and valve means responsive to operation of said pump for connecting the low pressure side of said pump piston to said intake and connecting the high pressure side of said pump piston to said conduit.

References Cited in the file of this patent v UNITED STATES PATENT S 866,592 Kimes Sept. 17, 1907 2,408,111 Truax Sept. 24, 1946 FOREIGN PATENTS 673,481 Great Britain June 4, 1952 OTHER REFERENCES Karcher (German publication), June 11, 1948. Astronautics (Journal of American Rocket Society), No. 34, June 1936, pp. 9, 12 and 13. 

